Botanists have classified the eultivated varie ties of the genus Tritieum into eight species and subspecies. The most important species, Triti cum. rulgure, comprises the common bread wheats, by far the most valuable and widely dis tributed group, containing more varieties than all the other species put together. This species includes soft and bard winter wheats. hard spring wheats, white wheats, and early wheats. The soft winter wheats are grown in the Eastern United States, Western and Northern Europe, Australia, Argentina, and in portions of Asia. The hard winter wheats are produced in the Rocky Mountains and the :Mississippi River re gions of the United States, in Southeastern Europe, and Western Asia. These wheats are usually grown on good black soils in regions of hot and dry summers. The bard spring wheats are distributed over the northern portion of the great plains in the United States. in Western Canada, Eastern Russia, and Western and South ern Siberia. The white wheats are cultivated along the Pacific coast in both North and South America, in Australia, and Western Asia. The early wheats occur in the Smaller') United States, Australia. India, and Japan. Only a few varieties are grown in the United States. The club or square-head wheats are by some botanists named Tritieunt compuetum. hut they are generally considered only a subspecies. The heads of this group are generally short and fre quently square. Club wheats are grown chiefly along the Pacific coast, and in Turkestan, Abys sinia, and in scattered districts of Europe. Tri tieum turgielum, or poniard wheat, is a subspe cies of Tritieum rulgure, distributed in the Med iterranean and the Mad: Sea regions. Some vari eties of this group are used in making macaroni. These wheats are sometimes mixed with the bread wheats in the manufacture of Hour. Tritieum durum is similar to Tritieum turyidum, and, like it. a subspecies of Triacum ruig«re. They are the hardest-grained of all the wheats grown, and are popularly known as the d11111111 or hard wheats. are specially valuable for the mnuiuEocttn•r of macaroni, for which purpose they, are mostly used. They are cultivated in the Mediterranean and Black Sea regions, and to some extent in Mexieo. Chile, and Argentina. Tritieum polonieum. or Polish wheat, is a dis tinct species, similar in quality to Tritieum durum, but much less frequently cultivated. Tri ticum Sprite, or spelt, although very different from the preceding groups is considered a sub species. Its striking characteristic is that the chaff adheres to the grain and is not removed in threshing. Spelt is grown in Central and Southern Europe, and to a very small extent in America. Eimer (Triticum dicoceum) resembles the preceding group and is often erroneously called spelt, from which it differs mainly in the very compact heads and harder grain of a deeper red color. Its distribution is about the same as that of spelt. Triticum monococcum, or Ein 1 corn. is a very distinct species. The spikelets of this species usually have but one grain. It is grown to a limited extent in Central and Southern Europe, Wheat requires a fertile and well-prepared soil. The fact that it makes a poor growth on light. humid. and acid soils shows the necessity of fertility and proper drainage. The most fa vorable soils are those which are permeable and deep, a little clayey and of medium fertility. Gravelly and sandy soils are not suited to its culture. It grows well on alluvial soils, and, in fact, on most soils which may be classed as heavy but which do not possess a very great tenacity. Since young wheat plants are readily injured by the heaving of the soil, due to the action of frost, perfect drainage is essential. Rolling the land before sowing winter wheat leaves the soil in a drier condition and thus minimizes the action of frost. Although the diameter of the soil mainly affects the yield, and the character of the climate the quality. friable, fertile, cal careous soils produce a softer, plumper, and starchier grain than a less fertile, light, clayey soil. This latter class of soils has a tendency to produce elongated, hard, glutinous grains, or a wheat having the qualities of a good bread wheat. The preparation of the land for winter wheat consists in plowing the soil about four or live inches deep as early in the season as possible, to allow it to become somewhat com pact before the seed is sown. The seed is sown broadcast or in drills. When broadcasted, usually by a machine made for the purpose, it is har rowed in. Drilling, however, is the most lar method and has the advantage of evenly dis tributing the seed and covering it at a uniform depth. The drill leaves the soil in small ridges. which tend to hold the snow and protect the soil to a certain extent against the alternate thaw ing and freezing so injurious to the crop. Spring wheat is usually grown on fall-plowed land, and in the United States also frequently follows a corn crop without plowing the soil. it is gen erally sown as soon as the soil is capable of be ing worked in the spring. Since wheat grows best and makes most of its growth during the cool part of the year, it should lie sown as soon as conditions will permit. A moist soil at sow ing time. provided it is not so moist that it cannot be properly worked, is the desirable con dition. Where wheat follows a corn prop (inaizo) without an intervening plowing of the soil. it is ,own broadcast among the corn stalks and the field then cultivated with a corn cultivator and the surface down by repeated harrow ing,. "-:oinetitnes the corn stalks are pit into short pieces with a stalk•culter before the seed is wINVII, whielt mikes the cultivating and liar rowing easier and more effective, but frequently the stalks are simply broken down by means of the harrow. If the stalks are not broken down
tlat to the ground they cause trouble in cutting the grain by machine.
Wheat is generally harvested before it has become dead ripe in order to prevent the grain from shattering during the different manipula tions from the time it is cut until it is stacked or threshed. In California, however, where this precaution is not so necessary, the harvest lasts for several weeks, and wheat is often left stand ing for a week or more after it is ripe enough for cutting. The time of harvesting wheat, like the time of sowing, varies with the latitude. In the United States the harvest begins in Texas early in May and ends in some of the Northern States in August. Harvesting is usually done with the self-binder, although in regions where labor is cheap the reaper is still largely used. After the grain has been bound into sheaves it is set up into shocks and left to dry and cure. Hound shocks are made if the main object is to protect the sheaves against the rain, but long shocks are required if the sheaves are wet or the grain is cut quite green. This expedites dry ing and curing. When the work of cutting and shocking is done the sheaves are hauled and. stacked, so until threshing time. The principal point to be observed in building a stack is that the sheaves, and especially the outer tier, must have an outward slant in order to shed the rain. In some countries, especially those of Europe. the stacks are built with great care and the grain is frequently not threshed until the following spring. In the 'United States threshing is usually completed in the fall. In sections of the United States where wheat is grown on an extensive scale, and the straw con sequently has little value, the grain is often harvested with headers, nr machines which cut the grain just below the head. Some of these machines, propelled by either horse or steam power, cut the heads and thresh out the grain at the same time. At the present. day wheat is threshed with improved and perfected machines operated by horse, steam. or electric power. The old method of flail threshing is now even less common than hand sowing. In Europe, where the straw represents a greater value than in the 'United States, machines are used which thresh the heads, but allow the straw to pass through straight and be rebound into sheaves for more • convenient storage.
In the United States the place of wheat in the rotation is generally after corn. since corn leaves the soil in clean condition. Where wheat is sown without, previously plowing, the ground it necessarily follows corn. The method of sow ing wheat among the corn stalks and working it in with cultivator and harrow is practicable only on comparatively new soils or lands in a very good condition. Tt. is largely practiced in regions newly opened up to cultivation. In Europe Wheat is preferably grown after clover. In the Eastern United States the use of com mercial fertilizers in wheat-growing is quito com mon. but in the western part of the country no fertilizers are applied. Barnyard manure is rarely applied directly to wheat. but usually to a preceding corn crop.
The wheat crop of the world in HMO amounted to 2,586,025,000 bushels. Of this amount Europe supplied 1,475,472,000 bushels. The total crop of the United States in 1899, according to the Twelfth Census, was 658,53-1,1:52 bushels, which was produced on 52,588,574 acres, or at an average rate of 12.5 bushels per acre. In 1898 the United States produced over 675,000,000 bushels, the largest crop over produced. The chief wheat-growing States and their production in 1899 as given by the Twelfth Census were: Minnesota, 95.279,660 bushels; North Dakota, 59,883,810 bushels; Ohio. 50.376,800 bushels; and South Dakota, 41,889,380 bushels. Kansas. Cali fornia, and Indiana in descending order of product produced over 30,001),000 bushels, and Nebraska, Missouri, Iowa, Washington, Pennsylvania, and Michigan 20,000,000 bushels. The progress of wheat cultivation in the Western States has been extremely rapid, due to the increase in wheat culture in previously unsettled regions. In 1821 the total exports of wheat from the the miller as `bran.' which forms about 1:; per cent. of the seed by weight. The innermost 1:iyer of the bran, averaging about 8 per cent. of the entire seed, contains cerealin or :tleurone, a nitrogenous substance. The bulk of the seed within this layer consists of starch, nitrogenous substances (espe cially gluten), and fat. \\•heat flour of various sorts is used almost universally for making bread and various kinds of pastry. Prom wheat rich in gluten, macaroni and other Italian pastes are made. These are common articles of diet in most countries, and staple articles in some, notably Italy. In recent years the consumption of breakfast foods made from wheat has increased very greatly. In sonic of these the grain is more or loss finely ground; in others it is rolled or• flaked. Some of these foods are cooked in the process of manufacture. Cereal breakfast foods are also made from the parched grain. The average composition of wheat and some of its products is shown in the following table: United States were valued at $178,314, and of wheat flour at $1,298,043; in 1900, $73.237.080 and $67,760,886, respectively. The largest aver age yield of wheat per acre is produced by Great Britain, followed by Germany, France, Hungary, Austria, the United States, and Russia, in the order mentioned. In total yield the United States leads all other countries.
The most common diseases to which wheat is subject are rust (Purr/flirt grain b? is), stinking smut, or bunt (Tinclia fmtens), and black or loose ( UrRtil(tgo trifle']) (see RUST: SMUTS: FUNEICIDE), and the most common insect enemies are the chinch bug and the Hessian fly (qq.v.).